Implications for public access defibrillation placement by non-traumatic out-of-hospital cardiac arrest occurrence in Singapore

Optimisation of the deployment of automated external defibrillators in public places in England

Background

Ambulance services treat over 32,000 patients sustaining an out-of-hospital cardiac arrest annually, receiving over 90,000 calls. The definitive treatment for out-of-hospital cardiac arrest is defibrillation. Prompt treatment with an automated external defibrillator can improve survival significantly. However, their location in the community limits opportunity for their use. There is a requirement to identify the optimal location for an automated external defibrillator to improve out-of-hospital cardiac arrest coverage, to improve the chances of survival.

Methods

This was a secondary analysis of data collected by the Out-of-Hospital Cardiac Arrest Outcomes registry on historical out-of-hospital cardiac arrests, data held on the location of automated external defibrillators registered with ambulance services, and locations of points of interest. Walking distance was calculated between out-of-hospital cardiac arrests, registered automated external defibrillators and points of interest designated as potential sites for an automated external defibrillator. An out-of-hospital cardiac arrest was deemed to be covered if it occurred within 500 m of a registered automated external defibrillator or points of interest. For the optimisation analysis, mathematical models focused on the maximal covering location problem were adapted. A de novo decision-analytic model was developed for the cost-effectiveness analysis and used as a vehicle for assessing the costs and benefits (in terms of quality-adjusted life-years) of deployment strategies. A meeting of stakeholders was held to discuss and review the results of the study.

Results

Historical out-of-hospital cardiac arrests occurred in more deprived areas and automated external defibrillators were placed in more affluent areas. The median out-of-hospital cardiac arrest - automated external defibrillator distance was 638 m and 38.9% of out-of-hospital cardiac arrests occurred within 500 m of an automated external defibrillator. If an automated external defibrillator was placed in all points of interests, the proportion of out-of-hospital cardiac arrests covered varied greatly. The greatest coverage was achieved with cash machines. Coverage loss, assuming an automated external defibrillator was not available outside working hours, varied between points of interest and was greatest for schools. Dividing the country up into 1 km2 grids and placing an automated external defibrillator in the centre increased coverage significantly to 78.8%. The optimisation model showed that if automated external defibrillators were placed in each points-of-interest location out-of-hospital cardiac arrest coverage levels would improve above the current situation significantly, but it would not reach that of optimisation-based placement (based on grids). The coverage efficiency provided by the optimised grid points was unmatched by any points of interest in any region. An economic evaluation determined that all alternative placements were associated with higher quality-adjusted life-years and costs compared to current placement, resulting in incremental cost-effectiveness ratios over £30,000 per additional quality-adjusted life-year. The most appealing strategy was automated external defibrillator placement in halls and community centres, resulting in an additional 0.007 quality-adjusted life-year (non-parametric 95% confidence interval 0.004 to 0.011), an additional expected cost of £223 (non-parametric 95% confidence interval £148 to £330) and an incremental cost-effectiveness ratio of £32,418 per quality-adjusted life-year. The stakeholder meeting agreed that the current distribution of registered publicly accessible automated external defibrillators was suboptimal, and that there was a disparity in their location in respect of deprivation and other health inequalities.

Conclusions

We have developed a data-driven framework to support decisions about public-access automated external defibrillator locations, using optimisation and statistical models. Optimising automated external defibrillator locations can result in substantial improvement in coverage. Comparison between placement based on points of interest and current placement showed that the former improves coverage but is associated with higher costs and incremental cost-effectiveness ratio values over £30,000 per additional quality-adjusted life-year.

Study registration

This study is registered as researchregistry5121.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (NIHR award ref: NIHR127368) and is published in full in Health and Social Care Delivery Research; Vol. 13, No. 5. See the NIHR Funding and Awards website for further award information.

Development of a centralised national AED (automated external defibrillator) network across all ambulance services in the United Kingdom

Background

Early cardiopulmonary resuscitation and defibrillation is key to increasing survival following an out-of-hospital-cardiac-arrest (OHCA). However, automated external defibrillators (AEDs) are used in a very small percentage of cases. Despite large numbers of AEDs in the community, the absence of a unified system for registering their locations across the UK's ambulance services may have resulted in missed opportunities to save lives. Therefore, representatives from the resuscitation community worked alongside ambulance services to develop a single repository for data on the location of AEDs in the UK.

Methods

A national defibrillator network, "The Circuit", was developed by the British Heart Foundation in collaboration with the Association of Ambulance Chief Executives, the UK ambulance services, the Resuscitation Council UK and St John Ambulance. The database allows individuals or organisations to record information about AED location, accessibility, and availability. The database synchronises with ambulance computer aided dispatch systems to provide UK ambulance services with real-time information on the nearest, available AED.

Results

The Circuit was successfully rolled out to all 14 UK ambulance services. Since 2019, 82,108 AEDs have been registered. Of the AED data collected by The Circuit, 54% were not previously registered to any ambulance service, and are therefore new registrations.

Conclusion

The Circuit provides ambulance services with a single point of access to AED locations in the UK. Since the launch of the system the number of defibrillators registered has doubled. Linking the Circuit data with patient outcome data will help understand whether improving the accessibility to AEDs is associated with increased survival.

Optimizing Outcomes After Out-of-Hospital Cardiac Arrest With Innovative Approaches to Public-Access Defibrillation: A Scientific Statement From the International Liaison Committee on Resuscitation

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Optimizing outcomes after out-of-hospital cardiac arrest with innovative approaches to public-access defibrillation: A scientific statement from the International Liaison Committee on Resuscitation

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Getting R-AEDI to save lives in Singapore

Early cardiopulmonary resuscitation (CPR) and defibrillation prior to the arrival of emergency medical services can improve survival from out-of-hospital cardiac arrest (OHCA) with good neurological outcome. However, the rate of local bystander CPR is only 24.3% and bystander defibrillation 2.1%. In 2015, the R-AEDI (Registry for AED Integration) initiative was started to improve OHCA survival rates. R-AEDI alerts volunteers to nearby OHCA cases via the myResponder mobile application. In 2015-2017, 7,682 AEDs were mapped and made accessible via this app. Comprehensive site inspections also resulted in fewer non-functional AEDs, as AED owners were educated on the importance of the maintenance of pads and batteries. The AED heat map allows us to identify areas that are lacking in or require improved public access AED coverage. The online AED registry found in the myResponder app is useful to locate AEDs rapidly during OHCAs. More community education would improve the rate of bystander defibrillation.

Ethnic and Neighborhood Socioeconomic Differences In Incidence and Survival From Out-Of-Hospital Cardiac Arrest In Singapore

Objective: We aimed to examine the association of ethnicity and socioeconomic status (SES) with Out-of-Hospital Cardiac Arrest (OHCA) incidence and 30-day survival in Singapore. Methods: We analyzed the Singapore cohort of Pan-Asia Resuscitation Outcome Study (PAROS), a multi-center, prospective OHCA registry between 2010 and 2015. The Singapore Socioeconomic Disadvantage Index (SEDI) score, obtained according to zip code, was used as surrogate for neighborhood SES. Age-adjusted OHCA incidence and Utstein survival were calculated by ethnicity and SES. Utstein survival was defined as the number of cardiac OHCA cases with initial rhythm of ventricular fibrillation witnessed by a bystander who survived 30-days or until hospital discharge. Logistic regression was used to investigate association of ethnicity with 30-day and Utstein survivals. Results: Our study population comprised 8,900 patients: 6,453 Chinese, 1,472 Malays, and 975 Indians. The overall age-adjusted incidence ratios (95% CI) for Malay/Chinese and Indian/Chinese were 1.93 (1.83-2.04) and 1.95 (1.83-2.08), respectively. The overall age-adjusted incidence ratios (95% CI) for average/low and high/low SEDI group were 1.12 (0.95-1.33) and 1.29 (1.08-1.53), respectively. Malay showed lesser Utstein survival of 8.1% compared to Chinese (14.6%) and Indian (20.4%) [p = 0.018]. Ethnicity did not reach statistical significance (p = 0.072) in forward selection model of Utstein survival, while SEDI score and category were not significant (p > 0.2 and p = 0.349). Conclusions: We found Malay and Indian communities to be at higher risks of OHCA compared to Chinese, and additionally, the Malay community is at higher risk of subsequent mortality than the Chinese and Indian communities. These disparities were not explained by neighborhood SES.

Singapore Defibrillation Guidelines 2016

The most common initial rhythm in a sudden cardiac arrest is ventricular fibrillation or pulseless ventricular tachycardia. This is potentially treatable with defibrillation, especially if provided early. However, any delay in defibrillation will result in a decline in survival. Defibrillation requires coordination with the cardiopulmonary resuscitation component for effective resuscitation. These two components, which form the key links in the chain of survival, have to be brought to the cardiac victim in a timely fashion. An effective chain of survival is needed in both the institution and community settings.

Public access defibrillation: improving accessibility and outcomes

BACKGROUND

Worldwide, out-of-hospital cardiac arrest (OHCA) remains a serious problem. Public access defibrillation (PAD) has been shown to be effective in improving survival in OHCA with good neurological outcome.

SOURCES OF DATA

Original articles, reviews and national/international guidelines.

AREAS OF AGREEMENT

Limitations to how much we can improve ambulance response times mean that the public have an essential role to play in OHCA survival. Training of laypersons in the use of automated external defibrillators (AEDs) has been shown to improve outcomes. Placement of AEDs should be related to underlying population demographics.

AREAS OF CONTROVERSY

Placements of AEDs face cost constraints. PAD programs also face challenges in the upkeep of AEDs. Concerns about legal liability for lay rescuers to act remain.

GROWING POINTS

Systematic programs should be in place to train the public in PAD. All AEDs should be listed in national registries and available for usage in an emergency.

AREAS TIMELY FOR DEVELOPING RESEARCH

'Smart' technology is being developed to improve accessibility of AEDs.